The shotgun floor technique. Whenever you have the high ground on someone it's very tempting to drop down and go for a heavy hitting shotgun shot. Unfortunately, shotguns are very inconsistent right now and dropping down into your enemy is very risky. This technique takes away all the risk of dropping down, but still allows you to get some insane head shots. Especially if you combine it with aimbots or similar cheats.
When built above someone, jump in the air and take a shot directly down at them. As soon as you shoot, place a floor underneath you to catch your fall. You can continue to do this to someone on the low ground allowing you to output a lot of damage without the risk of taking any the high ground pyramid.
To do this, place a ramp and then a pyramid. Once you're at the highest point of the pyramid place a floor and then jump onto it. This allows you to go a full story up very quickly. You can also do this twice in a row before your jump goes on cooldown. If you get this technique down fast enough you can even place a ramp on the floor you jumped on to allowing you to go two stories up extremely fast.